package com;
import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.PropertySource;import javax.sql.DataSource;
<context
public property_placeholder getLocation() {
        return location;
        }

        placeholder location='"classpath*:jdbc.properties"/>
@ProperiySource("classpath: jdbc.properties")
public class JdbcConfig {
    public class JdbcConfig (
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
}
<mapp
<!--根据id 查询图书信息 -->
<select id="findBookById" parameterType="int"resultType="com. itheima.domain.Book">select * from tb book where id = #(id)
</select>